The present invention relates to an apparatus for laminating multilayer identification cards which have relief-like surface.
For the manufacture of multilayer identification cards and the like, various methods are known. To manufacture identification cards with a planar surface, for example, use is made of two transparent films between which a paper blank is embedded on which all identification-card data, a passport photograph, and the like are imposed. In a single operation, the two outer layers and the information-carrying layer are so compressed under heat between two plane steel plates that the thermoplastic films, which become slightly pasty, penetrate into the pores of the paper and combine with the paper. Since the surfaces of the steel plates are planar, the surfaces of the identification cards become planar, too. Such cards with planar surfaces are very well suited for series manufacture, but their surfaces have no characteristics whatsoever which could prevent or show any attempted forgery and/or tampering thereof. In addition, the glossy card surface adversely affects the readability of the card data due to reflections under special lighting conditions.
To make it difficult to detach and reapply the transparent films, identification cards are known which have a raised seal, preferably in the picture or signature area. To manufacture such identification cards with raised patterns, the laminating apparatus is equipped with steel plates, for example, in which accurately positioned embossing dies are formed. Since the outer film become soft during the laminating process due to the applied heat, the embossing dies leave a permanent impression on the films (U.S. Pat. No. 3,533,176).
These identification cards have the disadvantage that, by reheating, the thermoplastic films can be "ironed" again and provided with new impressions at any time.
To avoid these disadvantages, identifications cards have been provided in which the paper blank is a security paper and in which the thickness differences of the paper blank, which are caused by watermarks, a safety thread, steel print, and the like, are visually, mechanically, and manually recognizable and detectable on the surface of the finished identification card. In such identification cards, the surface structure cannot be imitated by simple impression, and as a result of the manufacturing process being divided into different steps, subsequent attempts at lamination will be unsuccessful. Despite this very high safety against forgery and tampering, however, the wish for direct application to the card surface of similar raised patterns and particularly steel print has so far gone unfulfilled for lack of a suitable laminating technique. This is true particularly if signature strips provided with sensitive steel print or paper or film strips provided with similar relief print and intended for other purposes are to be laminated directly on to the surface of the identification card by a conventional laminating techniques. The inflexibility of the steel plates and the high laminating pressure damage the raised portions of the surface pattern in such a way that the quality of the identification cards so manufactured will not be satisfactory for the intended purpose of permitting easy verification of the authenticity of the card.